1. Field of the Invention
This invention refers to a ball joint with angular movement restriction system, for application in connections which require angular and rotational movement of two pieces, but whose angular movement needs to be restricted in a certain direction in order to achieve the desired effect, and more particularly, this invention is related to a ball joint to be applied in automotive vehicles.
2. Description of Related Art
Conventional construction of ball joints is based on a construction composed of a box or receptacle where there is housed a bearing, of single or split type, that houses a ball that is disposed as an integral part of the extremity of a pin, a so-called ball type (or ball) pin.
This set, duly mounted, has a fixing system in the external part of the box or receptacle, disposed at the extremity opposed to the ball, of the so-called ball type pin, in such a way that, when mounted in the box, it provides angular and rotating movements. These are the usual constructions of ball joints, generically utilized in the steering and suspension systems of vehicles. Depending on the specific located where they are to be applied, these ball joints have special characteristics design to enhance the operating requirements demanded by the pieces that must unite and articulate.
In order to overcome certain deficiencies associate with movement restriction, the state of the art utilizes the oblong opening of the joint box, common in this type of construction where it is projected to the body of the ball type pin, in such a way that the narrowest side of the opening; namely, the side that allows smaller angularity in the movement of the ball type pin, becomes coincident with the pin to restrict the movement of the ball type pin. This arrangement prevents the bar from spinning around its longitudinal axle. This technique however does not solve the problem because the body of the ball type pin of the joint is displaced itself until its maximum limit of angularity to that side and it abuts the oblong opening of the joint box. Thus, even if it partially solves the problem of rotation of the bar, it causes another problem, that is the inadequate operation of the ball joint with its ball type pin abutting against the opening of the box, outside of its geometrical axle, as it was designed. This inadequate operation of the ball joint will cause deficiency of movement, premature wearing out, noises and other undesirable inconveniences.
In an effort to solve the inconveniences of inadequate operation of the ball joint, some systems were developed that consist in replacing the cover of protection of the ball joint by a kind of rubber bushing that, when mounting the ball joint on the connecting bar, the bushing is compressed, producing a spring like effect. In cooperation with the narrowest part of the oblong opening of the joint box, the bushing attempts to prevent the rotation while at the same time holding, when the strain is not great, the ball type pin of the joint in the geometrical axle in which it was designed.
However, until now, also this technique has not presented the effects which are desirable, as when substituting the protection cover by the rubber bushing, this latter needs to be constructed in a way as to provide to the ball joint the same sealing effect as provided by the protection cover and, in order to achieve this objective it requires additional machining processes in the ball joint box and a special construction system for the rubber bushing, in order to make possible that it performs the two functions, namely, sealing the opening of the ball joint and that of providing a spring like effect so that the ball type pin of the joint is maintained in its designed geometrical axle. This system not only makes the end product expensive, but has a low index of applicability, since its use is limited to bars with short movement. Consequently, this system does not produce a great strain on the ball type pin and, further, in function of the constant strain upon the rubber bushing, this bushing tends to deteriorate before the working life time of the ball joint. Such results will affect the sealing system and consequently, with this wearing effect, the ball joint will be contaminated by impurities such as dust, sand and water, causing its premature wearing out.